The present invention relates to a tape printing apparatus and, in particular, but not exclusively, is concerned with a drive system for a tape printing apparatus. The present invention also relates to a supply of image receiving tape for a tape printing apparatus.
Known tape printing apparatus of the type with which the present invention is generally concerned are disclosed in European Patents, EP-A-322918 and EP-A-322919 (Brother Kogyo Kabushiki Kaisha) and European Patent EP-A-267890 (Varitronic). The tape printing apparatus have a cassette receiving bay for receiving a cassette or tape holding case. In EP-A-267890, the tape holding case houses an ink ribbon and a substrate tape, the latter comprising an upper image receiving layer secured to a backing layer by an adhesive. In EP-A-322918 and EP-A-322919, the tape holding case houses an ink ribbon, a transparent image receiving tape and a double-sided adhesive tape which is secured at one of its adhesive coated sides to the image receiving tape after printing and which has a backing layer peelable from its other adhesive coated side. With both these apparatus, the image transfer medium (ink ribbon) and the image receiving tape (substrate) are in the same cassette.
In all of these apparatus, the image receiving tape passes in an overlap matter with the ink ribbon to a print zone consisting of a fixed print head and a platen against which the print head can be pressed to cause an image to transfer from the ink ribbon to the image receiving tape. There are many ways of doing this, including dry lettering or dry film impression, but the most usual way at present is by thermal printing where the print head is heated and the heat causes ink from the ink ribbon to be transferred to the image receiving tape. Alternatively, the print head may be in direct contact with a thermally sensitive image receiving tape whereby when the print head is heated, an image is defined directly on the image receiving tape, without the need for an ink ribbon.
The known tape printing apparatus have input means, for example, a keyboard to allow the user to input an image to be printed. A display may be provided to display the input image and/or messages to the user. A cutting arrangement is provided to separate the image receiving tape on which an image has been printed from the supply of image receiving tape to thereby define a label.
European Patents EP-A-575772 (Esselte Meto International Produktions GmbH) discloses a thermal printer arranged to print bar code information or the like on discrete labels. The discrete labels may be supported on a backing sheet. Markings to identify the characteristics of the label may be provided either on the label itself or on the backing sheet. The markings, if provided on the label, are invisible. The markings are read by the thermal printer and may be used to determine whether an image should be printed directly on the label by the thermal printer or whether an ink ribbon is required to print an image on the label.
U.S. Pat. No. 4,531,850 (K.K. Sato) describes a printer which is arranged to print an image on a plurality of discrete labels carried on a backing web. Each label on the backing web has a mark thereon which is used to control the timing of the printing. In other words, the signal resulting from the detection of the marks on each label is used to control when the printer is activated so that the image falls within the label boundaries. Thus, a signal is sent to a control unit connected with a thermal head and the printing operations are conducted in response to the instructions coming from the control unit. The label maybe temporarily halted during printing.
Published International Application WO 96/04142 (Laser Master Corp.) describes a printer having the capability of multiple colour printing. Accordingly, a locating pattern is provided on the image receiving media to ensure that subsequent layers of colour correctly overlie previous layers. The markings on the print media are used to determine where printing should take place.
British Patent GB-A-2228449 (Tokyo Electric Co. Ltd.) discloses an ink ribbon for use in multiple colour printing. The ink ribbon has a plurality of colours sequentially aligned along the tape. Between the regions of different colours, colour recognition marks are provided so t hat the next colour can be identified. A plurality of evenly spaced markings are also provided on the tape from which the ribbon speed is determined. The speed of the ribbon varies as the ribbon spool is driven at a constant speed. The speed of the ink ribbon is used to correct readings obtained from the colour recognition marks so that the correct colour can be determined.
According to a first aspect of the present invention, there is provided a tape printing apparatus for printing an image on an image receiving tape, the apparatus comprising:
input means for receiving data defining an image to be printed on the image receiving tape;
receiving means for receiving a supply of image receiving tape;
printing means for printing an image on the image receiving tape;
detecting means for detecting markings provided on the image receiving tape, the markings being arranged to provide information on a characteristic of the image receiving tape; and
control means for controlling the tape printing apparatus in accordance with the detected image receiving tape characteristic.
Thus, it is possible to use the signals provided by the detecting means for controlling the printing apparatus in accordance with the detected image receiving tape characteristics. The image receiving tape may be provided with markings indicating, e.g. the tape width and/or printing energy required for obtaining optimal printing results. The tape printer can thus size the image to be printed according to the detected tape width and/or select the printhead energy appropriately. Further, the markings can represent tape background color, tape printing color or tape length. The latter characteristics will be primarily used for display purposes, informing the user about the parameters of the tape he is using. This aspect of the invention allows to dispense with representation means in a cassette (as disclosed, e.g. in EP-A-497352 or EP-A-534794) or in a tape replacement unit, as disclosed, e.g. in EP-A-635375, since only the image receiving tape as such is necessary for detecting the markings and hence controlling the printer. The invention is consequently applicable for image receiving tape provided in cassettes, and in replacement spools without any cassette, as well.
According to a second aspect of the present invention, there is provided a tape printing apparatus for printing an image on an image receiving tape, the apparatus comprising:
input means for receiving data defining an image to be printed on the image receiving tape;
receiving means for receiving a supply of the image receiving tape;
printing means for printing an image on the image receiving tape in accordance with the input data, the printing means being controlled by control means;
a drive system operable to drive the image receiving tape past the printing means; and
monitoring means for monitoring the speed of the image receiving tape, the monitoring means being arranged to detect markings provided on the image receiving tape and to provide a signal indicative of the speed at which the image receiving tape moves past the printing means, the monitoring means being connected to the control means for the printing means whereby the printing means is controlled in dependence on the speed of the tape.
By controlling the print head in dependence on the speed of the image receiving tape, it can be ensured that variations in the speed of the drive system or slippage between the drive system and the image receiving tape do not have an adverse effect on the printing. As the printing is controlled in dependence on the measured speed of the tape, variations in the speed of the tape are compensated for by the printing means. Furthermore, a direct correlation between the speed of the image receiving tape and the printing of the image thereon can be achieved.
Preferably, the drive system comprises a motor. The drive system may continuously drive the image receiving tape past the printing means. Alternatively, the image receiving tape may be driven stepwise past the printing means.
The motor may be a dc motor. However, any other suitable type of motor can also be used in embodiments of the present invention.
The input means may be in the form of a keyboard or the like or alternatively may be an input to receive a data stream from a computer or the like.
The markings may be detectable with electromagnetic radiation and the monitoring means preferably comprises a source of electromagnetic radiation and a detector to detect electromagnetic radiation from the source, after the electromagnetic radiation has interacted with the markings on the image receiving tape. The electromagnetic radiation can be any suitable type of radiation such as visible light, ultra violet light or infra-red radiation. The detector can be arranged to detect radiation transmitted through the image receiving tape or reflected therefrom.
The electromagnetic radiation source may comprise a light emitting diode and the detector may comprise a photo transistor. Thus, a cheap, yet effective, monitoring means can be achieved.
Preferably, a grating member is arranged between the detector and the image receiving tape, the grating member having at least one opening, or each opening of the grating may substantially correspond in size and shape to a single marking. It has been found that such a grating member improves the signal provided by the detector. Without the presence of the grating member, the signal provided by the monitoring means may be unsatisfactory or require increased manipulation. The grating member may enhance the differentiation between the markings and the surrounding regions so that a clearer signal is provided by the monitoring means. For example, where the markings are in the form of dark lines on a light background (or vice versa) the contrast between the light and dark regions is emphasised by the use of a grating member. In one preferred embodiment of the present invention, a plurality of openings are provided in the grating member. The spacing between adjacent openings preferably substantially corresponds to the spacing between adjacent markings on the image receiving tape. It is preferably that the width of each marking, the width of the space between each adjacent pair of lines and the width of each opening of the grating are the same.
In an alternative embodiment of the present invention, the monitoring means is operable to detect magnetic markings on the image receiving tape. The magnetic markings may be defined on the image receiving tape with magnetic ink, and the monitoring means may be operable to detect the markings defined by the magnetic ink. Alternatively, the magnetic markings may comprise a plurality of lines formed by recording flux reversals onto a magnetic strip on the image receiving tape, the monitoring means being arranged to detect the lines defined on the magnetic strip.
In the above described embodiments, the markings are preferably in the form of evenly spaced parallel lines extending perpendicular to the length of the image receiving tape. However, the markings may take any other suitable form. For example, the markings may be in the form of evenly spaced parallel lines extending at an angle to the length of the image receiving tape.
In one embodiment, at least one characteristic of the markings at or near an end of the image receiving tape is changed, the monitoring means being arranged to provide a signal indicative of the change in the characteristic of the markings to the control means so that an end of image receiving tape condition is determined. The characteristic of the markings which is changed may be one or more of the following characteristics: pitch of markings; width of each marking; color; and reflectivity of markings. In an alternative embodiment, an end of tape condition can be determined by the monitoring means if there is a lack of markings near or at the end of the image receiving tape.
In an alternative arrangement, the end of the image receiving tape is provided with means for resisting the separation from a supply reel for the image receiving tape, the monitoring means being arranged to provide a signal indicative of the reduction in speed of the image receiving tape caused by the resisting means at the end of the image receiving tape so that an end of tape condition is determined.
Thus, the markings provided on the image receiving tape can also be used in order to determine an end of tape condition as well as to control the printing. In the first described arrangement, the lack of or change in markings provides an indication of an end of tape condition, whereas in the second described arrangement, the reduction in detected speed of the image receiving tape provides an indication of the end of tape condition.
The markings on the image receiving tape are preferably arranged to also provide information as to the characteristics of the image receiving tape, the monitoring means being arranged to detect different markings on different types of image receiving tape and to provide a signal indicative of the different markings so that the characteristics of the image receiving tape are identified. These characteristics can include one or more of the following:
tape size;
tape color; and
nature of the image receiving tape such as whether or not an ink ribbon is required in order to print an image on the image receiving tape or if an image can be printed directly onto the image receiving tape without the need for an ink ribbon. The operation of the tape printing apparatus can be altered in dependence upon the detected characteristics of the image receiving tape. The pitch of the markings, the width of the markings, the color of the markings and/or the reflectivity of the markings on the image receiving tape may be varied in dependence on the characteristics of the tape, the monitoring means being arranged to provide a signal indicative of the detected markings. For example, when the speed of the image receiving tape is known (either detected eg. by an encoder on the shaft of the motor driving the tape, or determined by driving the motor with the appropriate parameters, eg. a stepper motor driven with a certain frequency of driving pulses), it is easily to judge from the frequency of detected pulses the pitch of the markings.
The tape printing apparatus is thus able to determine the nature of the inserted type of tape and control the operation of the apparatus accordingly. The apparatus may be arranged to store the information on the characteristics of the tape and only to carry out further checks when it is determined that the supply of image receiving tape may have been changed. For example, checks may only be carried out when it is detected that a lid to the tape receiving means has been opened or a supply of image receiving tape has been removed from the receiving means and replaced.
The drive system may be arranged to drive the image receiving tape backwards after a first image has been printed thereon, and when the image receiving tape is driven forwards again by the drive system a second image may be printed on the image receiving tape overlying the first image, the markings on the image receiving tape being used to position the image receiving tape so that the first and second images overlie one another. This feature is particularly advantageous for those embodiments where multi-color images are required so that images of more than one color overlie one another. In particular, full color printing can be achieved using this technique by using three images, one on top of each other, in cyan, magenta and yellow. Additionally, a further image in black may also overlie the first three images. Of course two tone printing can also be achieved with this technique. The number of images which overlie one another and the number of different colors can be selected as required by the user. Additionally, any color can be selected for the images which overlie one another.
Counting means may be provided for counting the number of markings which pass a given location when the tape is driven past the printing means in the forward direction and for counting the number of markings which pass the given location when the image receiving tape is driven backwards, the counting means being arranged to stop the driving of the image receiving tape in the backwards direction by the drive system when the number of markings which have passed the counting means substantially equals the number of markings counted when the image receiving tape is driven past the printing means in the forwards direction. In this way, an exact overlying of different images may be achieved. The counting means may comprise the monitoring means and the control means. The control means may A count the number of signals provided by the monitoring means. The control means may thus also control the drive system.
The printing means preferably comprises a thermal print head having a group of printing elements to which pixel data defining the image to be printed is passed sequentially on a group-by- group basis by the control means, the groups being sequentially printed adjacent one another in the direction of movement of the image receiving tape. Preferably, the sequential printing of the image on the image receiving tape is controlled by the control means in dependence on the speed of the image receiving tape. In this way, a correspondence between the speed of the image receiving tape and the control of the print head may be achieved.
Speed control means may be provided to control the speed of rotation of the motor to be at an approximately constant level. The speed control means may be coupled to the monitoring means, whereby the speed of the motor is controlled in dependence on the detected speed of the image receiving tape.
Preferably, the speed control means controls the speed of rotation of the motor to maintain the approximately constant level by applying a maximum drive to the motor if the speed of the image receiving tape detected by the monitoring means falls below a first predetermined value, no drive if the speed of the image receiving tape exceeds a second predetermined value and a linear drive versus speed characteristic if the speed of the image receiving tape is between the first and second predetermined values. With this relatively simple algorithm, it is possible to effectively control the speed of the motor within the bounds required by embodiments of the present invention. It should be appreciated that the speed of the image receiving tape provides a measure of the speed of the motor although, depending on the construction of any gear train between the motor and the drive for the image receiving tape, the speed of the image receiving tape may be higher or lower than the speed of rotation of the motor.
The monitoring means may be arranged to detect when a supply of image receiving tape is not present and to provide a signal indicative thereof.
The monitoring means may be arranged downstream of the printing means but is preferably arranged upstream thereof. Upstream of the printing means, the tape is under tension and accordingly there is less variation in its speed and position. Thus, more accurate speed and printing control can be achieved.
According to a third aspect of the present invention, there is provided a supply of image receiving tape arranged for use in a tape printing apparatus so that the image receiving tape can be driven past a print location and an image printed thereon, the image receiving tape comprising a continuous printing layer having a top printing surface for receiving a printed image and a rear adhesive surface and a continuous backing layer removable to uncover the rear adhesive surface of the top printing layer, the image receiving tape carrying along its length regularly spaced detectable markings to provide an indication of the speed at which the image receiving tape is driven past the printing location or an indication of a characteristic of the image receiving tape.
Preferably, the markings comprise a plurality of evenly spaced lines. The marking may be of a contrasting color to the color of the surface of the image receiving tape on which the markings are provided. The markings provided on the image receiving tape may be detectable by electromagnetic radiation. Alternatively, the markings may be magnetic. The magnetic markings may be defined by magnetic ink or the image receiving tape may include a magnetic strip on which the markings are defined. The markings may be provided on the surface of the image receiving tape on which an image is printed. Such markings are preferably invisible. However, the markings are preferably provided on the continuous backing layer. The location of markings on the backing layer may make it easier for the tape printing apparatus in which the supply is received to detect the markings, without interfering with the printing means. Additionally, if the markings are in any way heat sensitive, they are less likely to be effected if they are on the continuous backing layer which is further from the thermal print head than the layer on which the image is defined.
The supply of image receiving tape may be housed in a cassette. Preferably, at least one of the following marking parameters is used to provide information on the characteristics of the tape:
marking pitch; marking color; marking thickness; and marking reflectivity.
Preferably, a characteristic parameter of the markings is changed near an end of the image receiving tape to provide an end of tape indication.
According to a fourth aspect of the present invention, there is provided in combination, a tape printing apparatus for printing an image on an image receiving tape and a supply of image receiving tape, the image receiving tape comprising a surface for receiving a printed image and carrying along its length regularly spaced detectable markings, the tape printing apparatus comprising:
input means for inputting data defining an image to be printed on the image receiving tape;
receiving means in which the supply of the image receiving tape is received;
printing means for printing an image on the image receiving tape in accordance with the input data, the printing means being controlled by control means;
a drive system operable to drive the image receiving tape past the printing means; and
means for monitoring characteristics of the tape, whereby the monitoring means is arranged to detect the markings provided on the image receiving tape and provide a signal indicative of a parameter with which the markings move past the printing means, the monitoring means being connected to the control means for the print head so that the printing means is controlled in dependence on the characteristics of the image receiving tape.
According to a fifth aspect of the present invention, there is provided in combination, a tape printing apparatus for printing an image on an image receiving tape and a supply of image receiving tape, the image receiving tape comprising a surface for receiving a printed image and carrying along its length regularly spaced detectable markings, the tape printing apparatus comprising:
input means for inputting data defining an image to be printed on the image receiving tape;
receiving means in which the supply of the image receiving tape is received;
printing means for printing an image on the image receiving tape in accordance with the input data, the printing means being controlled by control means;
a drive system operable to drive the image receiving tape past the printing means; and
means for monitoring the speed of the image receiving tape, whereby the monitoring means is arranged to detect the markings provided on the image receiving tape and provide a signal indicative of the speed at which the image receiving tape moves past the printing means, the monitoring means being connected to the control means for the print head so that the printing means is controlled in dependence on the speed of the image receiving tape.
According to a sixth aspect of the present invention, there is provided a method of operating a method of operating a tape printing apparatus comprising input means for inputting data, receiving means for receiving a supply of image receiving tape and printing means for printing an image on image receiving tape, the method comprising the steps of:
inputting data defining the image to be printed via the input means;
driving the image receiving tape past the printing means;
detecting markings provided on the image receiving tape to thereby determine a characteristic of the image receiving tape; and
controlling the printing of the image on the image receiving tape by the printing means in dependence on the characteristic of the image receiving tape.
According to a seventh aspect of the present invention, there is provided a method of operating a tape printing apparatus comprising input means for inputting data, receiving means for receiving a supply of image receiving tape and printing means for printing an image on image receiving tape, the method comprising the steps of:
inputting data defining the image to be printed via the input means;
driving the image receiving tape past the printing means;
detecting markings provided on the image receiving tape to thereby determine the speed of the image receiving tape; and
controlling the printing of the image on the image receiving tape by the printing means in dependence on the speed of the image receiving tape.
According to a eighth aspect of the present invention, there is provided a tape printing apparatus for printing an image on an image receiving tape comprising:
means for receiving a supply of image receiving tape;
printing means for printing an image on the image receiving tape;
detecting means for detecting markings provided on the image receiving tape, the markings providing information on at least one characteristic of the image receiving tape, the detecting means comprising a source of electromagnetic radiation, a detector and a grating.
Preferably, the grating is provided between the detector and the image receiving tape.
The at least one characteristic of the tape includes one or more of the following characteristics:
tape speed; tape width; tape size; tape color; and printing method required to print an image for example whether or not an ink ribbon is required or if the image receiving tape is a direct thermal material.
According to a ninth aspect of the present invention, there is provided a tape printing apparatus for printing an image on an image receiving tape comprising:
means for receiving a supply of image receiving tape and an ink ribbon for providing an image on the image receiving tape;
printing means for printing an image on the image receiving tape using the ink ribbon;
detecting means for detecting markings provided on the ink ribbon, the markings being arranged to provide information on a characteristic of the ribbon; and
control means for controlling the tape printing apparatus in accordance with the detected ink ribbon characteristic.
The ink ribbon characteristic may be the speed of the ink ribbon; the colour of the ink ribbon; size of the ink ribbon; and/or any other property of the ink ribbon.